1. Field of the Invention
The present invention generally relates to devices used to detect and analyze respiratory sounds. More particularly, the invention is directed to a device used for the identification and monitoring of a parent's breathing patterns in a noisy ambient environment such as in a medical transport helicopter, aircraft, boat, ambulance, or other vehicle, or at a fire, disaster, sporting event, rock concert, or the like.
2. Description of the Prior Art
Traditional auscultation (i.e., listening) is an unacceptable method for monitoring the breathing patterns of a patient in a noisy ambient environment such as a medical transport helicopter or an ambulance. In short, experience with stethoscopes, amplified stethoscopes, and other listening devices has shown that even trained personnel are not able to distinguish respiratory sounds of a patient when the patient is located in a noisy ambient environment.
Cottrell et al., JAMA, 262:1653-1656 (1989), reported that during a one year study of medical emergencies on a commercial airline, the stethoscope was used in 80% of the instances when the on-board medical kit was required. However, a later letter to the Editor of JAMA by Bishop, JAMA, 263:233 (1990), and a reply by Cottrell and Kohn, JAMA, 263:233 (1990), indicated that in-flight auscultation attempts were unsuccessful due to the amount of ambient noise in the aircraft cabin. Cottrell and Kohn noted that ambient noise levels on board a commercial aircraft generally are low frequency, range upward to 65 dB [sic] and may approach 90 dB. They state that "At these levels, any worthwhile auscultation may be impossible, regardless of stethoscope type".
Hunt et al., JAMA, 265:1992-1994 (1991), reported that in no instances of in-flight experimental listening to recorded breath sounds emanating from the chest cavity of a resuscitation training manikin were medical personnel able to determine whether or not any breath sounds were present. This was true whether the in-flight nurses used conventional or amplified stethoscopes. Hunt et al. concluded that "Further research to develop new methods of breath sound assessment during air medical transport is urgently needed and will require the cooperative efforts of audiologists, engineers, air medical transport professionals, and physicians".
Similar poor results with stethoscopes were reported in Shenai, "Sound levels for neonates in transit", J. Pediat., 90:811-812 (1977).
Medical emergencies occur in a wide range of situations. Often, attending physicians or other medical emergency personnel must begin treatment of patients in less than ideal situaffons where ambient noise can impair the ability to detect audible respiratory sounds. Because breathing is a basic requirement of life itself, and often needs to be monitored in many medical emergencies, it would be advantageous to have equipment which allows for accurate detection and monitoring of a patient's breathing patterns. The above articles clearly indicate that present techniques of using stethoscopes is unsuitable. There is a need for an alternative device for detecting breathing signals.